Custom error message with Google Actions account linking?

Question

I have succesfully implemented the Account linking with Google Sign-in in my server.

The service logic goes like:

1. user authenticates with the server via browser, so I get his credentials
2. user authenticates with the server via Google Assistant/Home, then I match his credentials with its device

If a user skips step 1 and goes directly to step 2, my token endpoint replies with status 400 and the Assistant/Home replies:

Sorry, something went wrong, so I couldn't sign you in. But you can try again later.

Question: is there a way to change this to some custom message, like "You need to sign-in via browser first"?

Thanks!